The value of exfoliative sputum cytology in diagnosis of lung cancer has been accepted with bronchoscopic technique and results has been much improved by foreign investigators, but there was not presented accurate reports for sputum cytologic evaluation in Korea. We tried to find indicators of cytologic tests result in our hospital. During the period between May, 1980 and August, 1982, 400 patients, tested at Department of Thoracic and Cardiovascular Surgery of Kosin Medical College, had diagnostic bronchofiberscopic examination, and the cytologic study of sputum and bronchial secretions were performed. The sputum or bronchial secretion during bronchofiberscopic examination were obtained with various methods and the name of specimen were labeled as I, ASPIRATION SPUTUM, which was collected initially endobronchial sputum as introducing of scope, II, WASHING SPUTUM, which was collected washing bronchial secretion, III, BRUSHING SPUTUM, which was washing solution of brushing instrument and endobronchial sputum after brushing of lesions, IV, POST-SCOPIC SPUTUM, which was expectorated sputum as soon as removing of scopic instrument, V, ALL SPUTUM CYTOLOGY & CELL BLOCK, which was collected all specimen of above procedures. The diagnostic results of bronchofiberscopic examination was disclosed 174 cases [43.5%] of proved lung cancer, 47 cases [11.8%] of suspected lung cancer in grossly, and 179 cases [44.8%] of others finding except cancer. Patient with bronchofiberscopically grossly evidence of lung cancer which were not confirmed histologically or cytologically were excluded from this cytologic study. Histologic and cytologic correlation in proven lung cancer, 174 cases was revealed that number of cytologic positive patients were 45 cases [38.7%] among the 117 cases of proved squamous cell carcinoma, 12 cases [38.7%] among hislogically unknown cancer 34 cases and 6 cases [33.3%] among small cell undifferentiated carcinoma 18 Gases. Total cytologic positive result was presented as 67 cases [38.3%]. The other type of lung cancer, histologically, could not comparison because of small cases. The sequence of positive cytologic result in I-V specimen were disclosed as II, WASHING SPUTUM 57.6%, and V, ALL SPUTUM & CELL BLOCK 41.4%. The I, III & IV result were 28.6%, 22.2% and 26.1% respectively. [KTCS 1983;1:138-145]